Co-occurrence of Intracellular Adhesion Genes (icaA and icaD) Confers Higher Multi-drug Resistance on Staphylococucus aureus

Abstract

The importance of slime factor production in bacterial adherence, colonization and antibiotic resistance emphasizes it as a virulence associated macromolecules. This study was therefore aimed at investigating the presence of slime factor producing Staphylococcus aureus from different environmental sources and to correlate slime factor production with methicillin resistance distribution. A total of 384 samples (96 each of toilet seats, sewage samples, poultry droppings and street-vended salads) were collected according to the statistical scheme of the microbiological specification for foods and processed for Staphylococcus aureus isolation prior to slime factor production screening. Slime factor screening was carried out biphasically. First, by Congo Red Agar (CRA) technique and later by a primer specific polymerase chain amplification of icaA and icaD genes. Methicillin resistance was determined both phenotypically (by screening the susceptibility of Staphylococcus aureus to oxacillin) and genotypically (by amplification of mecA gene). The association between slime factor production and antibiotic resistance was estimated using chi-square (χ2). Result of the congo red technique depicts 43.9% of the 164 isolated Staphylococcus aureus (72) as slime producing strains while 9, 21 and 22 of the 72 Staphylococcus aureus show discrete amplification of icaA, icaD and cooccurrence of icaA and icaD respectively. Of the 52 molecularly confirmed slime producing Staphylococcus aureus strains, (43 (82.7) and 9 (17.3) were resistant and susceptible to oxacillin respectively) while 28(65.1%) exhibits discrete amplification of mecA gene. Our results however found significant association between slime factor production and antibiotic resistance